The display device such as an LCD (Liquid Crystal Display) forms an image by controlling individual image forming elements called pixels. This type of display device includes a display unit capable of displaying a pixel array and a driver which drives the display unit. An information processing device such as a computer, which is connected to the display device and displays an image on the display device, gives a display instruction to the driver, inputs data that is to be displayed in respective pixels and displays the image. The information processing device linking up with the display device such as this includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a DMA (Direct Memory Access) controller, etc.
FIG. 1 illustrates an outline of processes by a conventional information processing device. This information processing device displays a fixed background image and a dynamic image against the background image. Herein, the background image connotes an image representing, e.g., a car body and is stored as a pixel array in an address “0x8000” through an address “0x87FF” on a flash ROM in FIG. 1. On the other hand, the dynamic image is an illustration of a door in an open state in the car body. Moreover, the dynamic image is exemplified by displaying sensor data of respective portions in the car body such as data of a mileage, a car speed, an inclination of the vehicle, a temperature etc.
The display of the image is executed in the following procedures.
(1) At first, a DMA controller reads the image data representing the car body from the ROM and develops the image data on the RAM.
(2) Next, the CPU rewrites a segmental image of a portion that is changed with vehicle data, such as the door in the open state and a mileage display area. Such image data is thereby organized as to display the car body including the door in the open state or the present mileage in a lower position in an image screen of the car body.(3) An LCD controller outputs the image data organized on the RAM to the display device, e.g., an LCD.[Patent document 1] Japanese Patent Laid-Open Publication No. H04-277850